The present invention relates to an enclosure arrangement having a substantially ellipsoidal outer shape, constituted by two opposite elements which can be adjusted with respect to each other so that they can adapt to s the various heights (thickness) of the magnetic lamination pack of a series of small electric motors normally used to drive fans, pumps and the like.
It is well-known that a single-phase electric motor is usually constituted by a stator, a rotor which is rigidly coupled to the transmission shaft, and one or more excitation coils with corresponding leads. More specifically, low-power electric motors use as their stator a pack of magnetic laminations which is generally shaped like a parallelepiped and varies in thickness within preset limits according to the characteristics required by the user devices that the motor must drive.
It is also known that said lamination pack and said motion transmission shaft are not passed through by electric current during operation and therefore can be left exposed and not protected by a containment enclosure, whereas the winding coils and the leads are always live and therefore require protection with respect to all metallic and/or ferromagnetic parts; said protection can be constituted by an enclosure or by layers of insulating material which, in certain cases, can also constitute means for supporting the leads. Said metallic parts can be shaped so as to constitute feet, flanges or the like which are suitable to rigidly couple the motor to the device that uses the motor.
Moreover, low-power electric motors are generally marketed according to different power levels according to requirements, and these different power levels are obtained, for the same series of motors, by varying the height (thickness) of the lamination pack; accordingly, if the height of the lamination pack varies, an important dimension of the motor varies, and therefore the dimension of the containment enclosure also must vary; therefore, for each height of the pack it is necessary to have enclosures having different dimensions, with evident higher costs for investment in equipment to manufacture them and greater space occupation and inventory lock-up.
Currently, enclosures for these kinds of motor are often dimensioned so as to correctly contain the motor of the type having the highest pack, using them also for motors having a lower pack, with evident disadvantages both in terms of stability of the lower-height motors inside the enclosure and in terms of greater consumption of material.
Accordingly, the aim of the present invention is to provide an enclosure arrangement for low-power electric motors which is conceived and structured so as to fully obviate the above mentioned requirements and, more specifically, is such as to allow to protect with a single enclosure, both a motor with the lowest pack and a motor with the highest pack, thus is ensuring in any case maximum stability of the engagement between the enclosure and the motor.
An object of the invention is to provide an enclosure arrangement of the type with two elements or shells which are opposite to each other and mutually adjustable, each element being provided with openings which allow to leave when the enclosure is closed, the pack of magnetic laminations visible regardless of the height of the pack provided in a given series of motors.
Another object is to provide a protective enclosure arrangement for low-power electric motors which is externally provided with means for coupling the motor to a user device or to other supports, and also with seats suitable for the protrusion of the motor shaft from the enclosure and of the connector or cable that carries current to the windings.
Another object is to provide a protective enclosure arrangement for said motors which has a particularly pleasant outer shape and is highly effective in terms of distinctiveness.
This aim and these and other objects which will become better apparent hereinafter are achieved by an enclosure arrangement with mutually detachable elements, suitable for an entire series of small electric motors having different heights or thicknesses of the pack of magnetic laminations used, said enclosure being constituted, according to the present invention, by two half-shells or domes having a substantially ellipsoidal shape and provided with opposite identical cavities and with opposite ends that have different depths, a flat rectangular band being associated with the peripheral edge of one of said half-shells, or front half-shell, said band protruding from said edge and being interrupted in its central part in order to leave exposed the lamination pack enclosed between the two half-shells and create two mutually opposite band portions which are suitable to allow the opposite ends of the other half-shell, or rear shell, to be inserted slidingly under said band portions, so as to allow the rear half-shell to move with respect to the front half-shell in the case of lamination packs having different heights and up to the maximum height allowed by the provided series of motors, at least one of said half-shells further having means for anchoring the motor, enclosed and locked within the enclosure, to the user devices, seats for the passage of the motor shaft outside the enclosure, of the power connector or of the electric power supply cable, and seats for the ball bearings or other bearings that support the rotor.
More particularly, on the longitudinal arc-like edges of the two half-shells or covers rounded tabs are formed which are adapted to lock within corresponding slotted seats provided in the lamination pack, in order to ensure perfect closure positioning of the two half-shells with respect to the motor they protect, also compensating for any height tolerances of the lamination pack.